This invention relates to an interface circuit and more particularly to such a circuit adapted to provide speech outputs in response to digital stimuli.
It is often necessary for a telephone communication system to interface with automatic equipment for the provision of a service. For example, many buildings are now being controlled by computerized equipment and building users must sometimes report troubles, or provide information, to the control system over the PBX telephone system.
A problem exists in that the user, in order to communicate digitally with the system, must remember or look up a long list of number codes, each representing a different function to be performed by the system. While this may not present a great problem for routine requests from those who commonly use the system, it does, however, cause some users difficulty because they either do not remember or never had access to the list of codes.
The problem is compounded when the system response is tailored to a fluctuating set of circumstances. Thus, when the dialing of a particular digit code, say five, performs different functions depending upon some past action, the user can become easily confused.
As an answer to the problem, a system could be arranged to use a speech synthesizer interface to provide voice answerback capability in response to the transmittal of digital signals from a system user. Thus a user, operating from a telephone station, dials certain digits and the interface circuit provides voice instructions coaching the user as to which numbered buttons should be operated to achieve the desired result.
The straightforward manner of arranging such a system is to have the voice response limited only to the stimulus provided by the user. Thus, every response to a certain stimulus would always be identical. This is not acceptable when the response must be tailored to a combination of events or when the response is computer controlled. Accordingly, a need exists in the art for a voice answer circuit arranged to return to the user responses which are derived from an interaction of several independent input stimuli.
This need is motivated by those PBX customers who would like to provide access to data processing facilities or data services resources to a large number of users who do not have access to expensive data terminal equipment.
There are a wide variety of tasks relating to information retrieval, order entry and command/response whose implementation are unique to a specific customer. However, typically, the PBX manufacturer is not equipped to provide each customer with the necessary application software for every possible customer usage. On the other hand, the customer generally does not have the expertise to provide these applications because their implementation entails modifying software that provides the stored program control of the PBX. The dilemma then is that the owner of the PBX, who is the most intimately familiar with how features designed for his business should be implemented, does not have the expertise or knowledge to effect the necessary changes.
This invention addresses the issues of customer programmability of PBX services and the use of a standard telephone station set as a data terminal device. The device has a port circuit appearance in the system architecture and can send and receive data over the common bus described below. As with other port circuits, it receives control information over the bus from the call processor through a special message set. Rudimentary functions like call set up and maintenance are performed by the call processor. However, control of applications tasks such as playing speech and interpreting incoming dual tone multifrequency digits from the station set can be performed either by the call processor or some other data processing equipment supplied by the customer.